The invention concerns urea being condensated with other organic compounds with a plurality of nitrogen atoms such as amino compounds to produce amino condensation compounds. The invention also concerns their preparation and use. The amino condensation compounds are useful to produce flame retardant plastics and flame retard natural products, and may be reacted with phosphorus and/or boron containing compounds to produce other flame retardant compounds. The amino condensation compounds may also be reacted with aldehydes to produce amino condensation-aldehyde resins for use as molding compounds or as a flame retardant compound.
The heating of urea to produce urea condensation compounds, such as a mixture of cyanuric acid and cyamelide, is known in the arts, but the use of these compounds as a flame retardant is novel. The condensation of isocyanuric acid and/or cyanic acid, (which are produced by heating urea),with other nitrogen containing compounds to produce flame retardant compounds is novel. The amino condensation compounds and their phosphorus and/or boron salts are used as flame retardant compounds in plastics and natural products. Urea and melamine were utilized as a flame retardant compound by Fracalossi, et al., in U.S. Pat. No. 4,385,131. Melamine was utilized as flame retardant compounds in polyurethanes by Yukuta, et al., in U.S. Pat. No. 4,221,875 and by Grinbergs et al., in U.S. Pat. No. 4,745,133. Amino phosphates was utilized by Blount in U.S. Pat. No. 5,010,113.
What is lacking and what is needed are useful inexpensive nitrogen containing organic compounds with a plurality of nitrogen moieties. The amino condensation compounds and/or their salts of this invention are novel flame retardant compounds. The amino condensation compounds such as urea condensation compounds, urea-melamine condensation compound, urea-dicyandiamide compounds, urea-guanidine condensation compounds, etc., are novel flame retardant compounds. What is additionally lacking are compositions having such amino condensation compounds and/or their salts employed therein.
In one aspect, the invention comprises amino condensation compounds and their salts.
Another aspect of the invention is a process to prepare amino condensation compound and/or their salts comprising serially contacting
(A) urea
(B) nitrogen containing compound containing free NH2xe2x80x94COOH, xe2x80x94OH, xe2x80x94NCO and/or epoxide radicals that will condensate or react with urea;
under conditions sufficient to prepare the amino condensation compounds. The urea may be first reacted with itself then reacted with Component B or with more urea plus Component B or with Component B.
In another aspect, the invention comprises amino condensation salt of phosphorus and/or boron containing compound and a process to prepare a amino condensation salt of a phosphorus and/or boron containing compound, employing phosphorus and/or boron containing compound that will react with the amino condensation compound under conditions sufficient to prepare the amino condensation salt of a phosphorus and/or boron containing compound, and a process to prepare an amino condensation salts of a phosphorus and/or a boron containing compound comprising serially contacting
(A) urea;
(B) nitrogen containing compound containing reactive xe2x80x94NH2, xe2x80x94COOH, xe2x80x94OH, xe2x80x94NCO and/or epoxide radicals that will condensate or react with urea;
Components A and B are first reacted to produce an amino condensation compound then a phosphorus and/or boron containing compound that will react with an amino condensation compound is added mixed and reacted.
An addition aspect of this invention is the production of amino condensation-aldehyde resins and a process to prepare amino condensation-aldehyde resinous compound under conditions sufficient to prepare the amino condensation-aldehyde resin comprising serially contacting
(A) urea;
(B) nitrogen containing compound containing reactive xe2x80x94NH2, xe2x80x94COOH, xe2x80x94OH, xe2x80x94NCO and/or epoxide radicals that will condensate or react with urea;
Components A and B are reacted thereby producing an amino condensation compound then
(C) aldehyde;
(D) basic or acidic catalyst, are added and reacted.
An additional aspect of this invention is the production of flame retardant amino condensation compositions by mixing together the following components
A) amino condensation compound and/or amino condensation salt of a phosphorus and/or boron containing compound and/or amino condensation-aldehyde resin;
B) carbonization auxiliaries;
C) filler.
An additional aspect of the invention is the use of the amino condensation compounds in the production of flame retardant amino condensation salts of phosphorus and/or boron compounds, in the production of amino condensation-aldehyde resins and in the production of amino condensation compositions. The flame retardant use comprises contacting an otherwise more flammable organic material with the amino condensation compounds and/or amino condensation salts of phosphorus and/or boron containing compounds and/or amino condensation-aldehyde resins and/or amino condensation composition thereof under conditions sufficient to lower the combustibility of the otherwise more flammable organic material, for example plastics, natural products or polyurethanes. Thus, a further aspect of the invention is a flame-retardant composition comprising an otherwise more flammable organic material incorporated therewith a flame retardant amount of an amino condensation compound and/or a amino condensation salt of a phosphorus and/or boron containing compound, and/or amino condensation-aldehyde resin, carbonization auxiliaries and fillers.
The flame-retardant compounds of this invention are produced by heating urea (Component A) with a nitrogen containing compound (Component B) to above the melting point of urea to about 160 degree C. at ambient or increased pressure for 1-3 hrs. Upon heating above the melting point, urea form very reactive compound isocyanic acid and/or cyanic acid which will react with itself many times to form large molecules of cyamelide or with other organic or inorganic nitrogen containing compounds especially amino compounds. The condensation of urea by heating is illustrated as follows:
H2NCONH2xe2x86x92NH3+HNxe2x95x90Cxe2x95x90O⇄Nxe2x95x90COH 
wherein x is a number 3 to 10.
In order to increase the flame retardant properties and carbonization properties of the amino condensation compound a carbonization auxiliary, such as, phosphorus acidic compounds, organic phosphorus compounds that will react with an amino compound, boric acid, etc., is added to the melted amino condensation compound mixed and/or reacted. Other carbonization auxiliaries may be mixed with the amino condensation compounds to produce the flame retardant amino condensation composition. The amino condensation compounds may be further reacted with an aldehyde in the presence of a neutral or basic or acidic catalyst by mixing and heating the urea condensation compound with the aldehyde, usually in an aqueous medium, to just below the boiling point of the components at ambient or an elevated pressure thereby producing a urea condensation-aldehyde resin. The amino condensation salt of phosphorus compounds are produced by contacting the amino condensation compounds with a phosphorus containing compound that will react with an amino condensation compound, under conditions sufficient to prepare an amino condensation salt of a phosphorus containing compound. Fillers and carbonization auxiliaries may be added to the amino condensation compounds and/or amino salt of phosphorus and/or boron containing compounds and/or amino condensation-aldehyde resin. The amino condensation compounds and amino condensation-aldehyde resins with or without carbonization auxiliaries and fillers may be reacted with or added to or applied to a more flammable organic material.
The isocyanic acid may be reacted with itself to form biuret which is then reacted with an alkaline solution such as alkali metal hydroxides then neutralized with a metal sulfate such as cupric sulfate thereby forming a biuret-metal complex, which is then heated with component B to form a flame retardant amino-metal condensation compound.
Urea is utilized as component A and may be in the form of a powder, crystals or a solid. Urea is utilized in the amount of 50-100 parts by weight.
Any suitable nitrogen containing compound, especially those containing reactive xe2x80x94NH2, xe2x80x94COOH, xe2x80x94OH, xe2x80x94NCO, and/or epoxide radical, that will react with isocyanic acid and/or cyanic acid which is produced by heating urea may be utilized in this invention. The nitrogen containing compound may be an organic or an inorganic compound. Suitable organic nitrogen containing compounds may be an aliphatic, aromatic, cyclic, aliphatic-aromatic or aliphatic-cyclic compound such as, but not limited to, urea, urea derivatives for example, O-alkylureas, amino compounds, for example, melamine, melamine cyanurate, dicyandiamide, biuret, biuret-metal complex, guanidine, cyanoguanidine and aminoguanidine, ammonium carbonate, alkyl carbamates, alkyl isocyanates, polyisocyanates, sulfamic acid, ammonium sulfamate, amines, polyamines, thioureas, alkylanolamine, polyamides with free NH2xe2x80x94 radicals, amidines, amides, aldimines, ketimines, guanidine carbonate, amino carbonates, aminoborates, amino sulfates, thiourea, thiourea derivatives, compounds with active NH2xe2x80x94 radicals, such as amino phosphate, amino salts of organic phosphorus compounds and amino condensation salt of inorganic and organic phosphorus compounds containing active NH2xe2x80x94 radicals and mixtures thereof. The amino compounds are the preferred nitrogen containing compound. The nitrogen containing compound may be utilized in the amount of 10 to 200 parts by weight.
Any suitable carbonization auxiliaries may be utilized in this invention. Suitable carbonization auxiliaries are compounds that in the presence of fire assist the formation of a carbonization foam or char, such as, additives that produce acidic components in the pyrolysis mixture, such as phosphorus acids, boric acids or sulfuric acids. These acidic components are compounds such, for example, acids or salts, or their derivatives of sulfur, boron and phosphorus, such as, boron-phosphates, phosphates, and polyphosphates of ammonia, amines, polyamines, amino compounds, thioureas and alkyanolamines, but boric acid and its salts and their derivatives, organic phosphorus compounds and their salts, halogenated organic phosphorus compounds, their salts and their derivatives, silicon phosphorus halide compounds, their salts, and their derivatives, may also be used for this purpose. The carbonization auxiliaries and other flame retardant agents may be used in quantities of 1 to 300 parts by weight. The nitrogen containing salts of phosphorus acids are the preferred carbonization auxiliaries.
Any suitable organic material which is more flammable than the amino condensation compounds, its salts and amino condensation-aldehyde resin may be used in this invention. Any suitable plastic resin composition or mixtures thereof and any suitable natural organic material maybe used in this invention and mixtures thereof. These materials may be in the form of a solid, cellular suspension, emulsion or solution. Suitable plastic resin include, but not limited to, vinyl dienes, vinyl-diene copolymers, polyesters, polyester resins, phenoplasts, aminoplasts, polyepoxy resins, polyurethanes, furans, polyamides, polyimides, polycarbonates, homopolymers of such olefins as ethylene, propylene, and butylene; block copolymers, consisting of optional combination of these olefins; polymers of vinyl compounds such as vinyl chloride, acrylonitrile, methyl acrylates, vinyl acetates and styrene; copolymers of the foregoing olefins with vinyl monomers, copolymers and terpolymers of the foregoing olefins, with diene compounds; polyesters such as polyethylene terephthalate, polyester resins; polyamides such as nylon; polycarbonates, polyoxymethylene, silicones, polyethers, thioplasts, polytetrafluoroethylene, polysulfones, vinyldienes, poly(vinyl acetate), aliphatic allyl compounds, polyacrylonitrile, aliphatic dienes, polybutadiene, butadiene-acrylonitrile, butadiene-styrene copolymers, aromatic vinyl compounds, heterocyclic vinyl compounds, cyclic unsaturated compounds, urethane-epoxy resins, polyimides, urethane silicates, cellulose nitrate rayon, regenerated cellulose film cellulose acetate, cellulose esters, cellulose ethers, cyanoethyl cellulose, chlorinated rubber and mixtures thereof.
Suitable natural products include but not limited to wood, cellulose, lignin-cellulose, paper, starch, cotton, wool, linen, dammars, copols, other natural resins, rosins, lignin, natural rubber, natural proteins, e.g., soya bean protein, silk, glues, gelatin, etc.; modified cellulose and mixtures thereof. Natural organic material and plastics may be mixed together. The amino condensation compounds, its salts and amino condensation-aldehyde resin or amino condensation composition maybe utilized in the amount of 10-200 percent, percentage based on the weight of the more flammable organic material.
Suitable inorganic phosphorus compounds include, but not limited to, phosphoric acid, pyrophosphoric acid, triphosphoric acid, metaphosphoric acid, phosphorous acid, hydrophosphorous acid, phosphinic acid, phosphinous acid, phosphine oxide, phosphorus trihalides, phosphorus oxyhalides, phosphorus oxide, mono-metal hydrogen phosphates, ammonia dihydrogen phosphate, bromated phosphates, alkali metal dihydrogen phosphate and halogenated phosphate-phosphite and their halides and acids. Organic phosphorus compounds include, but not limited to, alkyl, cyclic, aryl and alkyl-aryl phosphorus compounds, such as, alkylchlorophosphines, alkyl phosphines, alkyl phosphites, dialkyl hydrogen phosphites, dialkyl alkyl phosphonates, trialkyl phosphites, organic acid phosphates, organic diphosphonate esters, aryl phosphites, aryl hydrogen phosphates, halogenated phosphonates esters and mixtures thereof may be used to produce amino condensation salts of phosphorus containing compounds. Amino condensation borates may be produced by contacting boric acid and amino condensation compound under conditions sufficient to prepare the amino condensation borates which may also be utilized as a flame-retardant compound. Amino condensation boron-phosphates may be produced by contacting boron-phosphates and amino condensation compounds under conditions sufficient to prepare amino condensation boron-phosphate compounds which may also be utilized as a flame-retardant compound. The salt forming phosphorus containing compounds will react with the amino condensation compounds to form an amino condensation salt of a phosphorus containing compound. Phosphoric acid is the preferred inorganic phosphorus containing compound. Dimethyl methyl phosphonate is the preferred organic phosphorus containing compound. Boric acid is the preferred boron containing compound. The phosphorus containing compound or boron containing compound or boron-phosphorus containing compounds are used in the amount of 10 to 100 parts by weight.
Any suitable aldehyde may be reacted with the amino condensation compounds. Suitable aldehydes include, but not limited to, formaldehyde, paraformaldehyde, acetoaldehyde, butyraldehyde, chloral, and other alkyl aldehydes, furfural, benzyl aldehyde and other aromatic aldehydes. Aqueous formaldehyde is the preferred aldehyde. The aldehyde is used in the amount of 10 to 100 parts by weight.
Any suitable filler may be used in this invention. The fillers that may be utilized in the flame retardant mixture are usually insoluble in the reaction mixtures. They may be inorganic substances, such as, alkali metal silicates, alkaline earth metal silicates, metal silicates, silica, metals and metal oxides, carbonates, sulphates, phosphates and borates, and glass beads or hollow glass beads. Hydrated aluminum oxide is preferred. They may be organic substances, such as, amino compounds, such as urea, melamine, dicyandiamide, and other cyanuric derivatives or their formaldehyde resins, aminophosphates, amino salts of organic phosphates, phenol-aldehyde resin powder, powdered coke, graphite, graphite compounds and mixtures thereof. The organic halide flame retardant compounds may also be added as fillers. The filler may be used in the amount of 1 to 300 parts by weight.
Any suitable basic or acidic catalyst may be used in the reaction of amino condensation compounds with aldehydes. Suitable basic compounds include but not limited to, compounds containing alkali metal, alkaline earth metal and ammonia radicals and mixture thereof. Suitable acidic compounds include, but not limited to, halogen acids, acidic phosphorus containing compounds, acidic compounds containing sulfur, sulphonic acid halides, carboxylic acids, polycarboxylic acids, nitric acids and mixtures thereof. In some reactions basic or acidic catalytic are not necessary. A catalytic amount is utilized and may range from the amount of 0.1 to 20 parts by weight.
In general, the amino condensation compounds are compounds which are produced by heating urea with other nitrogen containing compounds that will condensate or react with urea to produce amino condensation compounds. The heated urea first form isocyanic acid and/or cyanic acid which polymerizes with itself to form biuret, cyanuric and/or cyamelide. Large molecule of cyamelide may be formed in this process.
Any amount of the amino condensation compound or the amino condensation composition which includes the amino condensation compound and/or its salts and may include carbonization auxiliaries and fillers suitable for this invention may be utilized. Preferably, flame retardant amounts of the amino condensation compounds and/or its salts and/or the amino condensation-aldehyde resin or the amino condensation composition are from 10 percent by weight to about 200 percent by weight of the otherwise more flammable organic materials such as polyester resins, polyepoxy resins, polyurethane components, acrylic and acrylate resins, polyacrylonitrile, polystyrene, etc.
One method to measure this flame retardant capability is an oxygen index test. By selecting the various combinations of the amino condensation composition to incorporate into a more flammable organic material the average limiting oxygen index (LOI) can be raised 10 to 30 percent or more when compared to otherwise comparable samples without the flame retardant amino condensation compound or composition. For example the LOI of three flexible polyurethane foams with the amino condensation composition were raised more than 30 percent to a LOI of 31.7, 30.3 and 30.7.
When the amino condensation composition were incorporated into rigid polyurethane foam and tested with a propane torch with a 2xe2x80x3 flame held against the lower edge of the verticle held foam for one minute, the flame did not spread, the melted foam did not bum, a char was formed, the flame went out when the torch was removed and there was very little weight loss.
Various amino condensation compositions were incorporated into solid resins, for example, flexible polyepoxy resins, rigid polyepoxy resins, polyester laminating and flexible resin, polystyrene resin, polymethyl methyl acrylate resin, polyvinyl acetate resin, solid polyurethane, polyisoprene, acrylonitrile, etc, then tested with a propane torch having a 2xe2x80x3 flame held against the lower edge of the verticle sample for one minute, the flame did not spread, and went out when the flame was removed and there was very little weight loss. The said above material were tested without the amino condensation composition and all burned.
Various natural products such as wood shingles, paper, cotton cloth, and cardboard were coated with various amino condensation compositions in an aqueous emulsion containing 20% by weight of the powdered amino condensation composition then after the product had dried, then they were tested by applying a 2xe2x80x3 flame from a propane torch against the edge of the products, for 1 minute and the flame did not spread whereas the uncoated products caught on fire and burned.